JP7111162B2 - COMMUNICATION CONTROL DEVICE, METHOD AND PROGRAM - Google Patents

Description

The present invention relates to a communication control device, method, program, and computer-readable non-transitory recording medium.

In recent years, with the spread of highly functional mobile terminals such as smartphones and tablets, traffic via mobile networks is increasing.

It is difficult for the transmission rate control (for example, CUBIC, NewReno, etc.) used in many communications to follow rapid band fluctuations in mobile networks. As a result, bandwidth may be underutilized and throughput may decrease.

There is a technique for adjusting the transmission speed in a relay device that relays packets from a transmitter to a receiver. For example, in Patent Document 1, in a relay apparatus, an acknowledgment (acknowledgement: ACK) that would normally be sent by a receiving apparatus to the transmitting apparatus for data received from a transmitting apparatus is sent to the transmitting apparatus instead of the receiving apparatus. and adjusting the transmission rate to transmit the data to the receiving device. Patent Literature 2 also discloses a generally similar technique. In Patent Document 3, in a relay device, an available bandwidth of a network is estimated, a target transmission speed is estimated based on the available bandwidth, and an ACK to a transmission device is transmitted so that the target transmission speed approaches the current transmission speed. Techniques for adjusting the frequency of transmission of packets are disclosed.

JP 2003-124984 A WO2015/048999 JP 2018-067788 A

The techniques of Patent Documents 1 to 3 are based on the premise that the relay device can generate or modify an ACK packet as a proxy and transmit the ACK to the transmitting device.

However, due to the protocol used, it may not be possible for the relay device to generate and modify the ACK packet. As an example, an ACK packet may be encrypted or authenticated such that a relay device generates and modifies the ACK packet so that it cannot be sent or received. Also, when the ACK packet is encrypted, the relay device cannot grasp the acknowledgment number of the ACK packet, and cannot identify whether the packet has arrived normally or has been lost. Therefore, retransmission of the lost packet is promoted. ACK packets cannot be sent. In such a case, it becomes difficult to apply the techniques of Patent Documents 1 to 3.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a communication control apparatus and method capable of improving communication throughput between a transmitting apparatus and a receiving apparatus regardless of the protocol used.

A communication control apparatus according to an aspect of the present invention is a packet that is transmitted from a transmitting apparatus to a receiving apparatus and that cannot be generated and modified at a relay point between the transmitting apparatus and the receiving apparatus. a first communication processing unit for receiving from a device; and a second communication processing unit for transmitting the packet to the receiving device, wherein the second communication processing unit is an acknowledgment packet for the packet, receiving from the receiving device the acknowledgment packet that cannot be generated and modified at a relay point between the receiving device and the transmitting device, and transmitting the acknowledgment packet to the transmitting device; and a control unit for controlling the packet or the acknowledgment packet such that the transmission device changes the transmission speed.

A method according to an aspect of the present invention is a packet transmitted from a transmitting device to a receiving device, which cannot be generated and modified at a relay point between the transmitting device and the receiving device, from the transmitting device. receiving, transmitting said packet to said receiving device, and an acknowledgment packet for said packet, said acknowledgment not being able to be generated and modified at an intermediary point between said receiving device and said transmitting device; receiving packets from the receiving device; transmitting the acknowledgment packets to the transmitting device; and controlling the packets or the acknowledgment packets so that the transmitting device changes transmission speed. ,including.

A program according to an aspect of the present invention is a packet that is transmitted from a transmitting device to a receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device. receiving, transmitting said packet to said receiving device, and an acknowledgment packet for said packet, said acknowledgment not being able to be generated and modified at an intermediary point between said receiving device and said transmitting device. receiving packets from the receiving device; transmitting the acknowledgment packets to the transmitting device; and controlling the packets or the acknowledgment packets so that the transmitting device changes transmission speed. is a program that causes a processor to execute

A computer-readable non-transitory recording medium according to an aspect of the present invention is a packet transmitted from a transmitting device to a receiving device, which is generated and modified at a relay point between the transmitting device and the receiving device. receiving the packet from the transmitting device, transmitting the packet to the receiving device, and an acknowledgment packet for the packet, which is relayed between the receiving device and the transmitting device. receiving from the receiving device the acknowledgment packet that cannot be generated and modified at points; transmitting the acknowledgment packet to the transmitting device; It is a computer-readable non-transitory recording medium recording a program for causing a processor to control an acknowledgment packet.

According to the present invention, it is possible to improve the throughput of communication between a transmitting device and a receiving device regardless of the protocol used. It should be noted that other effects may be achieved by the present invention instead of or in addition to the above effects.

FIG. 10 is an explanatory diagram for explaining an example of changes in a congestion window (cwnd) in CUBIC; FIG. 4 is an explanatory diagram for explaining a technique for adjusting the amount of transmission data in BBR; 7 is a graph showing an example of changes in throughput due to fluctuations in the radio band and transmission rate control (CUBIC); FIG. 4 is an explanatory diagram for explaining an example of a QUIC packet; 1 is an explanatory diagram showing an example of a schematic configuration of a system according to an embodiment; FIG. 2 is a block diagram showing an example of a schematic functional configuration of a communication control device according to the first embodiment; FIG. 2 is a block diagram showing an example of a schematic hardware configuration of a communication control device according to the first embodiment; FIG. 4 is a sequence diagram for explaining an example of packet transmission from the transmitting device 10 to the receiving device 20 according to the first embodiment; FIG. 4 is a sequence diagram for explaining a first example of transmission timing adjustment according to the first embodiment; FIG. FIG. 9 is a sequence diagram for explaining a second example of transmission timing adjustment according to the first embodiment; FIG. 11 is a sequence diagram for explaining a third example of transmission timing adjustment according to the first embodiment; FIG. 5 is a sequence diagram for explaining an example of adjusting the transmission order of packets according to the first embodiment; FIG. 4 is a sequence diagram for explaining an example of discarding part of an ACK packet according to the first embodiment; 8 is a block diagram showing an example of a schematic functional configuration of a communication control device according to a second embodiment; FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the present specification and drawings, elements that can be described in the same manner can be omitted from redundant description by assigning the same reference numerals.

The description is given in the following order.
1. Related technology 2 . Configuration of system according to embodiment 3 . First Embodiment 3.1. Functional Configuration of Communication Control Device 3.2. Hardware configuration of communication control device 3.3. Technical features 4. Second Embodiment 4.1. Functional Configuration of Communication Control Device 4.2. Hardware configuration of communication control device 4.3. technical features

In this disclosure, the phrase "A and/or B" means "both A and B" or "either A or B."

<<1. Related technology >>
Techniques associated with embodiments of the present invention will be described with reference to FIGS.

(1) CUBIC
CUBIC is a congestion control method standardly used in TCP (Transmission Control Protocol) in Linux (registered trademark) kernel 2.6.19 and later. CUBIC is a method for controlling transmission speed based on the presence or absence of packet loss, and can be said to be a loss-based method.

FIG. 1 is an explanatory diagram for explaining an example of changes in a congestion window (cwnd) in CUBIC.

First, in the slow start phase, the transmitter increments cwnd by one packet each time an ACK is received. In this phase, cwnd increases exponentially over time. This increase continues until cwnd reaches a predetermined threshold (initial ssthresh).

Next, in the congestion avoidance phase, the transmitting device increases cwnd cubicly over time as long as ACKs are normally received. On the other hand, when the transmitting device receives duplicate acknowledgments (DupACK) for the same packet three times, it determines that the congestion is mild and decreases cwnd by a certain percentage (for example, 30%). , cwnd is set to 2 packets by judging severe congestion. In the example of FIG. 1, in the congestion avoidance phase, the transmitting device increases cwnd while normally receiving ACK, but decreases cwnd in response to the occurrence of DupACK or the like due to congestion. there is

Thus, in CUBIC, the transmitting device increases or decreases cwnd according to the ACK reception status. That is, the transmitting device changes the transmission speed according to the ACK reception status.

(2) BBR
BBR (Bottleneck Bandwidth and Round-trip propagation time) is a congestion control method that can be used in recent TCP, QUIC, and the like. BBR is a method for controlling transmission speed based on network performance estimated from packet transmission/reception, and can be said to be a function-based method.

Specifically, in BBR, a transmitting device estimates network performance while transmitting data, and determines the amount of data to be transmitted from the estimation result. Unlike CUBIC, even if packet loss occurs, the amount of transmitted data is not controlled.

In BBR, data is transmitted by adjusting the "pace" and "upper limit" of the amount of transmission data, and the "available bandwidth" and "communication delay" are continuously estimated. Specifically, as shown in FIG. 2, the transmitting device increases the pace and increases the upper limit with 'STARTUP', decreases the pace and increases the upper limit with 'DRAIN', and increases the upper limit with 'PROBE_BW'. 'PROBE_RTT' sets the pace to normal (slight fluctuation) and the upper limit to normal, and 'PROBE_RTT' sets the pace to normal and the upper limit to a minimum.

The transmitting device estimates the maximum value of "arrival confirmation data amount/elapsed time" within a certain period of time as the "available bandwidth", and estimates the minimum value of the RTT (Round Trip Time) within the certain period of time as the "communication delay". . The "available bandwidth" is called BtlBw (Bottleneck Bandwidth), and the "communication delay" is called RTprop (Round-Trip propagation time):.

Furthermore, the transmitting device calculates the "transmission data amount" by multiplying the "available bandwidth" and the "communication delay". This "transmission data amount" is called BDP (Bandwidth-Delay Product).

(3) Throughput in Mobile Networks In recent years, with the spread of sophisticated mobile terminals such as smartphones and tablets, traffic via mobile networks has increased. It is difficult for the transmission rate control (for example, CUBIC, NewReno, etc.) used in many communications to follow rapid band fluctuations in mobile networks.

FIG. 3 is a graph showing an example of changes in throughput due to fluctuations in the radio band and transmission rate control (CUBIC). Referring to FIG. 3, the throughput changes due to the transmission rate control (CUBIC) by CUBIC according to the fluctuation of the radio band, but the throughput cannot sufficiently follow the fluctuation of the radio band due to the drastic fluctuation of the radio band.

(4) QUIC
QUIC (Quick UDP Internet Connections) is a transport protocol and is used as an upper layer protocol of UDP (User Datagram Protocol). QUIC has a packet configuration that makes it extremely difficult for an intermediate device to generate or modify packets.

FIG. 4 is an explanatory diagram for explaining an example of a QUIC packet. Referring to FIG. 4, a QUIC packet is shown as an SDU (Service Data Unit) of a UDP packet. A QUIC packet includes a QUIC packet header and a payload, which includes one or more QUIC frames. Each QUIC frame includes a QUIC frame header and QUIC data. The payload within the QUIC packet is encrypted. Also, the QUIC packet header is unencrypted but authenticated and immutable.

<<2. Configuration of system according to embodiment>>
An example of a system configuration according to an embodiment of the present invention will be described with reference to FIG.

FIG. 5 is an explanatory diagram showing an example of a schematic configuration of the system 1 according to the embodiment of the invention. Referring to FIG. 5 , system 1 includes transmitter 10 , receiver 20 and communication control device 100 . The communication control device 100 may be called a relay device.

The transmitting device 10 transmits packets to the receiving device 20 . The communication control device 100 is located between the transmitting device 10 and the receiving device 20 and transfers (or relays) the packets. Specifically, the communication control device 100 receives the packet from the transmitting device 10 via the transmitting network 30 and transmits the packet to the receiving device 20 via the receiving network 40 . For example, the packet is a data packet.

As an example, when a user downloads content, the sending device 10 may be a server and the receiving device 20 may be a personal computer (PC) or smart phone. In this case, the receiving network 40 may be a mobile network, the Internet, or may include the Internet and a mobile network. Alternatively, if the user uploads content, the sending device 10 may be a personal computer (PC) or smart phone, and the receiving device 20 may be a server. Of course, the transmitting device 10 and the receiving device 20 are not limited to these examples.

The transmitter 10 uses a transmission control scheme to control the transmission rate. As an example, the transmission control method is a first transmission control method (for example, a loss-based transmission control method such as CUBIC) that controls the transmission speed based on the presence or absence of packet loss. Alternatively, the transmission control method is a second transmission control method (for example, a function-based transmission control method such as BBR) that controls the transmission speed based on network performance estimated from packet transmission/reception. Of course, the above transmission control method is not limited to these examples. Note that the transmission control method can also be called a congestion control method.

<<3. First Embodiment>>
A first embodiment of the present invention will be described with reference to FIGS.

<3.1. Functional Configuration of Communication Control Device>
FIG. 6 is a block diagram showing an example of a schematic functional configuration of the communication control device 100 according to the first embodiment. Referring to FIG. 6, the communication control device 100 includes a first communication processing unit 110, a second communication processing unit 120, a current transmission speed estimation unit 130, a target transmission speed estimation unit 140, a transmission control estimation unit 150, and a control unit 160. Prepare.

The first communication processing unit 110 transmits and receives packets. For example, the first communication processing unit 110 receives packets (eg, data packets) from the transmitting device 10 and transmits packets (eg, ACK packets) to the transmitting device 10 .

The second communication processing unit 120 transmits and receives packets. For example, the second communication processing unit 120 transmits packets (eg, data packets) to the receiving device 20 and receives packets (eg, ACK packets) from the receiving device 20 .

The first communication processing unit 110 and the second communication processing unit 120, for example, process one or more protocol layers. Specifically, for example, the one or more protocol layers include layer 3 (network layer) and higher protocol layers. The one or more protocol layers may further include protocol layers below Layer 2. Alternatively, the one or more protocol layers may include only protocol layers from Layer 2 onwards. Also, the first communication processing unit 110 and the second communication processing unit 120 may be integrated as one communication processing unit.

Current transmission speed estimation section 130 estimates the current transmission speed between transmitting device 10 and receiving device 20 for each session or stream related to packets transferred by communication control device 100 .

The target transmission speed estimation unit 140 estimates the target transmission speed between the transmission device 10 and the reception device 20 for each session or stream related to packets transferred by the communication control device 100 .

The transmission control estimation unit 150 estimates the transmission control method used by the transmission device 10 for each session or stream related to packets transferred by the communication control device 100 .

The control unit 160 controls packets transmitted from the transmitting device to the receiving device. For example, the control may be an ACK packet for the packet (the ACK packet received from the receiving device 20 by the second communication processing unit 120 and transmitted to the transmitting device 10 by the first communication processing unit 110) or the packet (the 1 communication processing unit 110 receives from the transmitting device 10 and the second communication processing unit 120 transmits the data packet to the receiving device 20). The control unit 160 may indirectly control the ACK packet or the packet by controlling the operation of the first communication processing unit 110 or the second communication processing unit 120 . Alternatively, the control unit 160 directly controls the ACK packet or the packet by directly processing the ACK packet or the packet between the first communication processing unit 110 and the second communication processing unit 120. may be performed.

More specific operations of the first communication processing unit 110, the second communication processing unit 120, the current transmission speed estimation unit 130, the target transmission speed estimation unit 140, the transmission control estimation unit 150, and the control unit 160 are described in the first implementation. It will be explained later as a technical feature of the form.

<3.2. Hardware Configuration of Communication Control Device>
FIG. 7 is a block diagram showing an example of a schematic hardware configuration of the communication control device 100 according to the first embodiment. Referring to FIG. 7, communication control device 100 includes processor 210 , main memory 220 , storage 230 , communication interface 240 and input/output interface 250 . Processor 210 , main memory 220 , storage 230 , communication interface 240 and input/output interface 250 are interconnected via bus 260 .

Processor 210 executes a program read from main memory 220 . As an example, the processor 210 is a CPU (Central Processing Unit).

The main memory 220 stores programs and various data. As an example, the main memory 220 is RAM (Random Access Memory).

The storage 230 stores programs and various data. As an example, the storage 230 includes SSDs (Solid State Drives) and/or HDDs (Hard Disk Drives).

Communication interface 240 is an interface for communication with other devices. As an example, communication interface 240 is a network adapter or network interface card.

The input/output interface 250 is an interface for connection with an input device such as a keyboard and an output device such as a display.

The first communication processing unit 110 and the second communication processing unit 120 may be implemented by the processor 210 and the main memory 220, or may be implemented by the processor 210, the main memory 220 and the communication interface 240. Current transmission rate estimator 130 , target transmission rate estimator 140 , transmission control estimator 150 and/or controller 160 may be implemented by processor 210 and main memory 220 .

Of course, the hardware configuration of the communication control device 100 is not limited to this example. Communication control device 100 may be implemented with other hardware configurations.

Alternatively, the communication control device 100 may be virtualized. That is, the communication control device 100 may be implemented as a virtual machine. In this case, the communication control device 100 (virtual machine) may operate as a virtual machine on a physical machine (hardware) including a processor, memory, etc. and a hypervisor.

Communication control device 100 may include a memory (main memory 220) that stores programs (instructions) and one or more processors (processor 210) that can execute the programs (instructions). The one or more processors execute the above program to perform the first communication processing unit 110, the second communication processing unit 120, the current transmission speed estimation unit 130, the target transmission speed estimation unit 140, the transmission control estimation unit 150 and/or Alternatively, the operation of the control unit 160 may be performed. The program causes the processor to execute the operations of the first communication processing unit 110, the second communication processing unit 120, the current transmission speed estimation unit 130, the target transmission speed estimation unit 140, the transmission control estimation unit 150 and/or the control unit 160. It may be a program for

<3.3. Technical features>
Technical features of the first embodiment will be described with reference to FIGS. 8 to 12. FIG.

(1) Packet Relay The communication control device 100 (first communication processing unit 110 ) receives from the transmitting device 10 packets transmitted from the transmitting device 10 to the receiving device 20 . The communication control device 100 (second communication processing unit 120 ) then transmits the packet to the receiving device 20 .

For example, the packet is a data packet. For example, the packets are packet data units (PDUs). Instead of being called packets, the packets may be called frames, datagrams or other similar names such as segments.

Furthermore, the communication control device 100 (second communication processing unit 120 ) receives an acknowledgment (ACK) packet for the packet from the receiving device 20 . Then, the communication control device 100 (first communication processing unit 110 ) transmits the acknowledgment (ACK) packet to the transmission device 10 .

FIG. 8 is a sequence diagram for explaining an example of packet transmission from the transmitting device 10 to the receiving device 20 according to the first embodiment. The transmitting device 10 transmits a packet (data packet) 51 to the receiving device 20 (S301, S303). At this time, the communication control device 100 receives the packet 51 from the transmitting device 10 (S301) and transmits the packet 51 to the receiving device 20 (S303). That is, the communication control device 100 transfers (or relays) the packet 51 from the transmission device 10 to the reception device 20 . Further, the receiving device 20 receives the packet 51 (S303) and transmits an ACK packet 53 for the packet 51 to the transmitting device 10 (S305, S307). At this time, the communication control device 100 receives the ACK packet 53 from the receiving device 20 (S305), and transmits the ACK packet 53 to the transmitting device 10 (S307). That is, the communication control device 100 transfers (or relays) the packet 53 from the receiving device 20 to the transmitting device 10 .

(2) Packets and Acknowledgment (ACK) Packets The above-mentioned packets transmitted from the transmitting device 10 to the receiving device 20 are generated and It is a packet that cannot be altered.

Furthermore, an acknowledgment (ACK) packet for the above packet is an ACK packet that cannot be generated and modified at a relay point between the receiving device 20 and the transmitting device 10 .

More specifically, for example, the packet and the ACK packet are at least partially encrypted or authenticated. Among other things, the encrypted or authenticated part of the ACK packet contains information for acknowledgment to the sending device 10 (eg an acknowledgment number, etc.).

As a first example, transmitting device 10 transmits at least partially authenticated packets and receiving device 20 transmits at least partially authenticated ACK packets. In this case, since the packet and the ACK packet are authenticated, the communication control device 100 cannot generate or modify the packet and the ACK packet.

As a second example, the transmitting device 10 transmits at least partially encrypted packets, and the receiving device 20 transmits at least partially encrypted ACK packets. In this case, since the packet and the ACK packet are encrypted, the communication control device 100 cannot generate or modify the packet and the ACK packet.

As an example, the packet is a QUIC packet (eg, as shown in FIG. 4) and the ACK packet for the packet is also a QUIC packet. In this case, for example, the information (for example, the acknowledgment number) for the acknowledgment to the transmitting device 10 is the authenticated header of the ACK packet (QUIC packet) or the encrypted header of the ACK packet (QUIC packet). Included in payload. As another example, the packet may be a QUIC frame (eg, as shown in FIG. 4) and the ACK packet for the packet may also be a QUIC frame. In this case, the information for the acknowledgment to the transmitting device 10 (eg, acknowledgment number) may be included in the encrypted ACK packet (QUIC frame).

(3) Packet Control The communication control device 100 (control unit 160) controls the above-described packets transmitted from the transmitting device 10 to the receiving device 20, and performs the control to change the transmission speed of the transmitting device 10. conduct.

For example, the control is an ACK packet for the packet or control of the packet.

(3-1) Control based on current transmission speed and target transmission speed Estimation of current transmission speed For example, communication control device 100 (current transmission speed estimation unit 130) estimates the current transmission speed of transmission device 10 .

For example, the communication control device 100 (current transmission speed estimation unit 130) estimates the RTT based on the time stamp information or the like included in the header of the packet received from the transmission device 10, and is estimated as the current transmission speed (cwnd) of the transmission device 10 .

For example, in this way, the current transmission rate may be the amount of data transmitted during the RTT. Alternatively, the current transmission rate may be the amount of data transmitted per unit time (throughput).

Estimation of Target Transmission Speed For example, the communication control device 100 (target transmission speed estimator 140 ) estimates the target transmission speed of the transmission device 10 .

For example, the communication control device 100 (target transmission speed estimating unit 140) sets the available band on the side of the transmitting network 30 (hereinafter referred to as "first available band") and the available band on the side of the receiving network 40 (hereinafter referred to as called "second available bandwidth"). Then, the communication control device 100 (target transmission rate estimator 140) obtains a first value obtained by multiplying the first available band by the RTT, and a first value obtained by multiplying the second available band by the RTT. One of the second value (eg, the smaller value) is estimated as the target transmission rate.

Estimation of the first available bandwidth (available bandwidth on the transmission side network side) may be estimated as the first available bandwidth.
[Example 1] "data packet size/data packet reception interval" (or its statistical value)
[Example 2] "Packet group size / Time taken to receive packet group" (or statistical value thereof) (Packet group is a set of data packets received at intervals of less than a threshold or within a certain period of time)

Estimation of second available band (available band on receiving side network side) As an example, communication control device 100 (target transmission rate estimator 140) estimates one of the following examples as the second available band. may
[Example 1] "Amount of data whose arrival is confirmed by an ACK packet / ACK packet reception interval" (or its statistical value)
[Example 2] "Amount of data confirmed arrival by ACK packet group / Time taken to receive it" (or its statistical value) set)
[Example 3] Reduction rate of data packets accumulated in the communication control device 100

After accumulating the data packets received from the transmission device 10, the communication control device 100 (the target transmission speed estimation unit 140) collectively transmits the data packets to the reception side network 40, thereby temporarily achieving the second The second available bandwidth may be estimated by transmitting data packets at a transmission rate exceeding or close to the available bandwidth.

When estimating the second available bandwidth, the communication control device 100 (target transmission speed estimation unit 140) estimates the past receiving device that has the same or similar network performance from information such as the destination IP address. It is also possible to use the track record of communication

Control based on estimation results For example, the communication control device 100 (control unit 160) controls the packet based on the current transmission speed and the target transmission speed (control for causing the transmission device 10 to change the transmission speed )I do.

For example, the communication control device 100 (control unit 160) performs the control so that the transmission speed of the transmission device 10 approaches the target transmission speed.

As an example, when the difference between the target transmission speed and the current transmission speed (target transmission speed−current transmission speed) is greater than a predetermined threshold (any positive number or 0), the communication control device 100 (Control unit 160) performs the above-described control (control for increasing the transmission speed of the transmitting device 10). If the difference between the current transmission speed and the target transmission speed (current transmission speed - target transmission speed) is greater than a predetermined threshold (any positive number or 0), the communication control device 100 (control unit 160) may perform the above-described control (control for causing the transmission device 10 to reduce the transmission speed).

As another example, the communication control device 100 (control unit 160) sets a control parameter according to the difference between the target transmission speed and the current transmission speed (target transmission speed−current transmission speed), The above control may be performed using parameters.

(3-2) First example of control: adjustment of transfer timing For example, the control includes adjustment of the transmission timing of the ACK packet or the packet. That is, the communication control device 100 (control unit 160) adjusts the transmission timing of the ACK packet or the packet.

First Example As a first example, the adjustment of the transmission timing includes shortening the transmission interval between the ACK packets. That is, the communication control device 100 (control unit 160) shortens the transmission interval between the ACK packets.

FIG. 9A is a sequence diagram for explaining a first example of transmission timing adjustment according to the first embodiment. The communication control device 100 (second communication processing unit 120) receives the ACK packets 55, 57, 59 from the receiving device 20 (S321, S323, S325). Communication control apparatus 100 accumulates ACK packets 55, 57, and 59 without transmitting them immediately to transmitting apparatus 10, and transmits ACK packets 55, 57, and 59 at predetermined intervals 91 (short intervals). As a result, the transmitting device 10 receives the ACK packets 55, 57, and 59 in a short time, and the transmitting device 10 counts a large amount of arrival-confirmed data in a short time. The predetermined interval 91 may be a predetermined control parameter, or may be a control parameter set by the communication control device 100 (control unit 160).

As a result, for example, it is possible to make it appear to the transmitting device 10 that the data packets have been collectively transmitted. As a result, for example, when the transmission device 10 uses a function-based transmission control method (such as BBR), the maximum value of the available bandwidth increases, and the amount of transmission data can increase. That is, the transmission speed of the transmitting device 10 can be increased, and the throughput of communication between the transmitting device 10 and the receiving device 20 can be improved.

The adjustment of the transmission timing may include shortening the transmission interval between the packets (data packets) (rather than the transmission interval between the ACK packets). That is, the communication control device 100 (control unit 160) may shorten the transmission interval between the packets (data packets). Also in this case, as a result, the transmission interval between ACK packets is also shortened, so a similar effect can be obtained.

Second Example As a second example, the adjustment of the transmission timing includes lengthening the transmission interval between the ACK packets. That is, in the second example, contrary to the first example, the communication control device 100 (control unit 160) lengthens the transmission interval between the ACK packets.

FIG. 9B is a sequence diagram for explaining a second example of transmission timing adjustment according to the first embodiment. The communication control device 100 (second communication processing unit 120) receives the ACK packets 55, 57, 59 from the receiving device 20 (S321, S323, S325). Communication control device 100 transmits ACK packets 55, 57, and 59 at predetermined intervals 92 (long intervals). As a result, the transmission device 10 receives the ACK packets 55, 57, and 59 for a long period of time, and the amount of arrival-confirmed data counted per fixed period in the transmission device 10 decreases. The predetermined interval 92 may be a predetermined control parameter, or may be a control parameter set by the communication control device 100 (control unit 160).

This makes it possible, for example, to make it appear to the transmitting device 10 that the data packets are transmitted little by little. As a result, for example, when the transmitting device 10 uses a function-based transmission control method (for example, BBR), the maximum value of the available bandwidth becomes small, and the amount of transmission data can become small. That is, the transmission speed of the transmitting device 10 may decrease, and the communication throughput between the transmitting device 10 and the receiving device 20 may decrease.

The adjustment of the transmission timing may include lengthening the transmission interval between the packets (data packets) (rather than the transmission interval between the ACK packets). That is, the communication control device 100 (control unit 160) may lengthen the transmission interval between the packets (data packets). In this case as well, the transmission interval between ACK packets is lengthened as a result, and a similar effect can be obtained.

Third Example As another example, the adjustment of the transmission timing may include delaying transmission of the ACK packet. Communication control device 100 (control unit 160) may delay transmission of the ACK packet.

FIG. 10 is a sequence diagram for explaining a third example of transmission timing adjustment according to the first embodiment. The communication control device 100 (second communication processing unit 120) receives the ACK packet 61 from the receiving device 20 (S341), but does not immediately transmit the ACK packet 61 to the transmitting device 10. is transmitted to the transmitting device 10 (S343). Similarly, the communication control device 100 (second communication processing unit 120) receives the ACK packet 63 from the receiving device 20 (S345), but does not immediately transmit the ACK packet 63 to the transmitting device 10, and after a predetermined time 93 The ACK packet 63 is transmitted to the transmitting device 10 (S347). The predetermined time 93 may be a predetermined control parameter, or may be a control parameter set by the communication control device 100 (control unit 160).

This makes it possible, for example, to increase the RTT (the time from when the transmitting device 10 transmits a packet until it receives an ACK). For example, when the transmission device 10 uses a loss-based transmission control method (for example, CUBIC, etc.), as a result, the allowable waiting time for retransmission becomes longer (for example, the value of RTO (Retransmission Time Out) becomes larger). . Therefore, when a sudden delay occurs, it is possible to avoid retransmission and the accompanying reduction in transmission speed. Alternatively, if the transmission device 10 uses a function-based transmission control scheme (such as BBR, for example), the estimated communication delay will increase as a result. Therefore, the amount of transmission data can become large. That is, the transmission speed of the transmitting device 10 can be increased, and the throughput of communication between the transmitting device 10 and the receiving device 20 can be improved.

Note that the adjustment of the transmission timing may include delaying the transmission of the packet (data packet) (rather than the ACK packet). Also in this case, the RTT is increased as a result, and a similar effect can be obtained.

(3-3) Second example of control: adjustment of transfer order For example, the control includes adjustment of the transmission order of the packets. That is, the communication control device 100 (control unit 160) adjusts the transmission order of the packets.

Specifically, for example, the adjusting the transmission order is adjusting the transmission order of the packets such that the packets are transmitted in sequence order rather than in the order received. That is, the communication control device 100 (control unit 160) adjusts the transmission order of the packets so that the packets are transmitted in sequence order, not in reception order. For example, the communication control device 100 (control unit 160) adjusts the transmission order of the packets buffered in the communication control device 100 so that the packets are transmitted in sequence order.

FIG. 11 is a sequence diagram for explaining an example of packet transmission order adjustment according to the first embodiment. The transmitting device 10 transmits packets 65, 67, 69, 71 and 73 (S361-S371), and the communication control device 100 receives and buffers the packets 65, 67, 69, 71 and 73. FIG. Packets 65, 67, 69, and 71 are new packets, while packet 73 is a resent packet. Therefore, packet 73 (retransmitted packet) is the last packet among packets 65, 67, 69, 71, and 73 in order of reception, but the first in order of sequence. Therefore, the communication control device 100 first transmits packet 73 (retransmission packet) to the receiving device 20 (S371), and then transmits packets 65, 67, 69, and 71 in sequence order to the receiving device 20 (S373 to S379). ).

Thereby, for example, retransmission packets can be preferentially transferred. As a result, retransmitted packets become acknowledged packets sooner after a packet loss occurs, the amount of packets remaining in the transmission window drops sooner, and more new packets can be sent. That is, the transmission speed of the transmitting device 10 can be increased, and the throughput of communication between the transmitting device 10 and the receiving device 20 can be improved.

Also, when the packets transmitted from the transmission device 10 do not arrive at the communication control device 100 in sequence, the packets may be transmitted in sequence. Therefore, packets are more likely to arrive at the receiving device 20 in sequential order, and the possibility of duplicate acknowledgments (DupACKs) for the same packet being generated is reduced. For example, when the transmission device 10 uses a loss-based transmission control method (for example, CUBIC, etc.), there is a possibility that multiple (for example, three or more) duplicate acknowledgments (DupACKs) for the same packet will occur consecutively. is lowered, and a drop in transmission speed (eg, a drop in cwnd) can be suppressed. That is, communication throughput between the transmitting device 10 and the receiving device 20 can be improved.

(3-4) Third Example of Control: Partial Discard of ACK Packet For example, the control includes discarding part of the ACK packet. That is, the communication control device 100 (control unit 160) discards part of the ACK packet.

For example, the discarding is discarding acknowledgment packets at a predetermined probability, at a predetermined rate, or at predetermined time intervals. That is, the communication control device 100 (control unit 160) discards ACK packets at a predetermined probability, at a predetermined rate, or at predetermined time intervals. The predetermined probability, the predetermined ratio, and the predetermined time interval may be predetermined control parameters, or may be control parameters set by the communication control device 100 (control unit 160). good.

FIG. 12 is a sequence diagram for explaining an example of discarding part of an ACK packet according to the first embodiment. The receiving device 20 transmits the ACK packet 75 to the transmitting device 10 (S381, S383). The communication control device 100 receives the ACK packet 75 from the receiving device 20 (S381), and transmits the ACK packet 75 to the transmitting device 10 (S383). The receiving device 20 transmits the ACK packet 77 to the transmitting device 10 (S385). However, the communication control device 100 receives the ACK packet 77 from the receiving device 20 (S385) and discards the ACK packet 77 (S387). The receiving device 20 transmits the ACK packet 79 to the transmitting device 10 (S389, S391). The communication control device 100 receives the ACK packet 79 from the receiving device 20 (S389), and transmits the ACK packet 79 to the transmitting device 10 (S391). As a result, when the ACK packet 79 is received in the transmitting device 10, a large amount of data whose arrival has been confirmed is counted at once.

As a result, for example, it is possible to make it appear to the transmitting device 10 that the data packets have been collectively transmitted. As a result, for example, when the transmission device 10 uses a function-based transmission control method (such as BBR), the maximum value of the available bandwidth increases, and the amount of transmission data can increase. That is, the transmission speed of the transmitting device 10 can be increased, and the throughput of communication between the transmitting device 10 and the receiving device 20 can be improved.

Further, even if duplicate acknowledgments (DupACKs) for the same packet occur, there is a possibility that a plurality of (for example, three or more) duplicate acknowledgments (DupACKs) for the same packet are received in succession by the transmitting device 10. lower. Therefore, for example, when the transmission device 10 uses a loss-based transmission control method (for example, CUBIC), a decrease in transmission speed (for example, a decrease in cwnd) can be suppressed. That is, communication throughput between the transmitting device 10 and the receiving device 20 can be improved.

(3-5) First, Second, and Third Examples of Control As the control, adjustment of the transmission timing of the ACK packet or the packet, adjustment of the transmission order of the packet, and adjustment of part of the ACK packet Destroy explained. The control may include all of adjusting the transmission timing, adjusting the transmission order, and discarding a part of the ACK packet, or may include only a part of it. For example, the control may be one of adjusting the transmission timing, adjusting the transmission order, and discarding some of the ACK packets.

(3-6) Others Communication control apparatus 100 (transmission control estimation unit 150, control unit 160) estimates the transmission control scheme used by transmission apparatus 10, and performs the above control based on the estimated transmission control scheme. may be performed.

For example, the communication control device 100 (control unit 160) selects control (for example, adjustment of transmission timing, adjustment of transmission order, or discarding part of the ACK packet) that conforms to the estimated transmission control scheme. , may be executed. Alternatively, communication control apparatus 100 (control unit 160) may select a control parameter suitable for the estimated transmission control method, and perform control using the control parameter.

Thereby, for example, the transmission speed of the transmission device 10 can be changed more appropriately.

The first embodiment has been described above. According to the first embodiment, as described above, it is possible to improve the throughput of communication between the transmitting device 10 and the receiving device 20 regardless of the protocol used.

<<4. Second Embodiment>>
A second embodiment of the present invention will now be described with reference to FIG. While the first embodiment described above is a specific embodiment, the second embodiment is a more generalized embodiment.

<4.1. Functional Configuration of Communication Control Device>
FIG. 13 is a block diagram showing an example of a schematic functional configuration of the communication control device 300 according to the second embodiment. Referring to FIG. 13 , the communication control device 300 includes a first communication processing section 310 , a second communication processing section 320 and a control section 330 .

The first communication processing unit 310 transmits and receives packets. For example, the first communication processing unit 310 receives packets (eg, data packets) from the transmitting device 10 and transmits packets (eg, ACK packets) to the transmitting device 10 .

The second communication processing unit 320 transmits and receives packets. For example, the second communication processing unit 320 transmits packets (eg, data packets) to the receiving device 20 and receives packets (eg, ACK packets) from the receiving device 20 .

The control unit 330 controls packets transmitted from the transmitting device to the receiving device. For example, the control may be an ACK packet for the packet (the ACK packet received from the receiving device 20 by the second communication processing unit 320 and transmitted to the transmitting device 10 by the first communication processing unit 310) or the packet (the 1 communication processing unit 310 receives from the transmitting device 10 and the second communication processing unit 320 transmits the data packet to the receiving device 20). The control unit 330 may indirectly control the ACK packet or the packet by controlling the operation of the first communication processing unit 310 or the second communication processing unit 320 . Alternatively, the control unit 330 directly controls the ACK packet or the packet by directly processing the ACK packet or the packet between the first communication processing unit 310 and the second communication processing unit 320. may be performed.

More specific operations of the first communication processing unit 310, the second communication processing unit 320, and the control unit 330 will be described later as technical features of the second embodiment.

<4.2. Hardware Configuration of Communication Control Device>
The hardware configuration of the communication control device 300 according to the second embodiment is, for example, the same as the hardware configuration of the communication control device 100 according to the first embodiment. Therefore, redundant description is omitted here.

<4.3. Technical features>
Technical features of the second embodiment will be described.

(1) Packet Relay The communication control device 300 (first communication processing unit 310 ) receives from the transmitting device 10 packets transmitted from the transmitting device 10 to the receiving device 20 . The communication control device 300 (second communication processing unit 320 ) then transmits the packet to the receiving device 20 .

The description of this point according to the second embodiment is, for example, the same as the description of this point according to the first embodiment (except for the difference in symbols). Therefore, redundant description is omitted here. However, of course, the second embodiment is not limited to this example.

(2) Packets and Acknowledgment (ACK) Packets The packets transmitted from the transmitting device 10 to the receiving device 20 are generated and It is a packet that cannot be altered.

Furthermore, an acknowledgment (ACK) packet for the above packet is an ACK packet that cannot be generated and modified at a relay point between the receiving device 20 and the transmitting device 10 .

The description of this point according to the second embodiment is, for example, the same as the description of this point according to the first embodiment (except for the difference in symbols). Therefore, redundant description is omitted here. However, of course, the second embodiment is not limited to this example.

(3) Packet Control The communication control device 300 (control unit 330) controls the above-described packets transmitted from the transmitting device 10 to the receiving device 20, and controls the transmitting device 10 to change the transmission speed. conduct.

The description of this point according to the second embodiment is, for example, the same as the description of this point according to the first embodiment (except for the difference in symbols). Therefore, redundant description is omitted here. However, of course, the second embodiment is not limited to this example.

The second embodiment has been described above. According to the second embodiment, it is possible to improve the throughput of communication between the transmitting device 10 and the receiving device 20 regardless of the protocol used.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Those skilled in the art will appreciate that these embodiments are illustrative only and that various modifications can be made without departing from the scope and spirit of the invention.

For example, the steps in the processes described herein do not necessarily have to be executed in chronological order according to the order described in the sequence diagrams. For example, the steps in the process may be performed in an order different from that depicted in the sequence diagrams, or in parallel. Also, some of the steps in the process may be deleted and additional steps may be added to the process.

Also, components of the communication control device described in this specification (for example, the first communication processing unit, the second communication processing unit, the current transmission speed estimation unit, the target transmission speed estimation unit, the transmission control estimation unit and/or the control unit ) may be provided. A method may also be provided that includes the processing of the above components, and a program may be provided for causing a processor to execute the processing of the above components. Also, a non-transitory computer readable medium recording the program may be provided. Of course, such devices, modules, methods, programs, and computer-readable non-transitory recording media are also included in the present invention.

Some or all of the above embodiments may also be described in the following additional remarks, but are not limited to the following.

(Appendix 1)
A communication control device,
a first communication processing unit that receives from the transmitting device a packet that is transmitted from the transmitting device to the receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device;
a second communication processing unit that transmits the packet to the receiving device;
with
The second communication processing unit receives from the receiving device an acknowledgment packet for the packet that cannot be generated and modified at a relay point between the receiving device and the transmitting device. ,
The first communication processing unit transmits the acknowledgment packet to the transmitting device,
The communication control device is
a control unit that controls the packet or the acknowledgment packet so that the transmission device changes the transmission speed;
further comprising
Communications controller.

(Appendix 2)
2. The communication control apparatus according to appendix 1, wherein the control includes adjustment of transmission timing of the acknowledgment packet or the packet.

(Appendix 3)
The communication control apparatus according to appendix 2, wherein the adjustment of the transmission timing includes shortening or lengthening the transmission interval between the acknowledgment packets or the transmission interval between the packets.

(Appendix 4)
4. The communication control device according to appendix 2 or 3, wherein said adjustment of said transmission timing includes delaying transmission of said acknowledgment packet or said packet.

(Appendix 5)
5. The communication control device according to any one of appendices 1 to 4, wherein the control includes discarding part of the acknowledgment packet.

(Appendix 6)
The communication control device according to appendix 5, wherein the discarding is discarding the acknowledgment packet at a predetermined probability, at a predetermined rate, or at predetermined time intervals.

(Appendix 7)
7. The communication control device according to any one of appendices 1 to 6, wherein the control includes adjustment of the transmission order of the packets.

(Appendix 8)
8. The communication control device of claim 7, wherein the adjusting the transmission order is adjusting the transmission order of the packets such that the packets are transmitted in sequence rather than in the order received.

(Appendix 9)
the packet is a packet at least partially encrypted or authenticated;
the acknowledgment packet is an acknowledgment packet that is at least partially encrypted or authenticated;
The communication control device according to any one of Appendices 1 to 8.

(Appendix 10)
The communication control device according to appendix 9, wherein the part of the acknowledgment packet includes information for acknowledgment to the transmitting device.

(Appendix 11)
a target transmission speed estimating unit that estimates a target transmission speed between the transmitting device and the receiving device;
further comprising
The control unit performs the control based on the target transmission speed.
11. The communication control device according to any one of Appendices 1 to 10.

(Appendix 12)
a current transmission speed estimator for estimating a current transmission speed between the transmitting device and the receiving device;
further comprising
The control unit performs the control based on the current transmission speed and the target transmission speed.
The communication control device according to appendix 11.

(Appendix 13)
a transmission control estimation unit that estimates a transmission control scheme used by the transmission device;
further comprising
The control unit performs the control based on the estimated transmission control scheme.
13. The communication control device according to any one of Appendices 1 to 12.

(Appendix 14)
The transmitting device is a transmitting device that uses a first transmission control scheme or a second transmission control scheme,
The first transmission control method is a transmission control method for controlling a transmission speed based on the presence or absence of packet loss,
The second transmission control method is a transmission control method that controls a transmission speed based on network performance estimated from packet transmission and reception,
14. The communication control device according to any one of Appendices 1 to 13.

(Appendix 15)
15. The communication control device according to any one of appendices 1 to 14, wherein the packet is a data packet.

(Appendix 16)
receiving from the transmitting device a packet that is transmitted from the transmitting device to the receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device;
transmitting the packet to the receiving device;
receiving from the receiving device an acknowledgment packet for the packet, which acknowledgment packet cannot be generated and modified at an intermediary point between the receiving device and the transmitting device;
transmitting the acknowledgment packet to the transmitting device;
controlling the packet or the acknowledgment packet so that the transmitting device changes transmission rate;
method including.

(Appendix 17)
receiving from the transmitting device a packet that is transmitted from the transmitting device to the receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device;
transmitting the packet to the receiving device;
receiving from the receiving device an acknowledgment packet for the packet, which acknowledgment packet cannot be generated and modified at an intermediary point between the receiving device and the transmitting device;
transmitting the acknowledgment packet to the transmitting device;
controlling the packet or the acknowledgment packet so that the transmitting device changes transmission rate;
A program that causes the processor to execute

(Appendix 18)
receiving from the transmitting device a packet that is transmitted from the transmitting device to the receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device;
transmitting the packet to the receiving device;
receiving from the receiving device an acknowledgment packet for the packet, which acknowledgment packet cannot be generated and modified at an intermediary point between the receiving device and the transmitting device;
transmitting the acknowledgment packet to the transmitting device;
controlling the packet or the acknowledgment packet so that the transmitting device changes transmission rate;
A computer-readable non-transitory recording medium that records a program that causes a processor to execute

This application claims priority based on Japanese Patent Application No. 2018-129929 filed on July 9, 2018, and the entire disclosure thereof is incorporated herein.

1 system 10 transmitter 20 receiver 100, 300 communication control device 110, 310 first communication processor 120, 320 second communication processor 130 current transmission speed estimator 140 target transmission speed estimator 150 transmission control estimator 160, 330 control unit

Claims (8)

A communication control device,
a first communication processing unit that receives from the transmitting device a packet that is transmitted from the transmitting device to the receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device;
a second communication processing unit that transmits the packet to the receiving device;
with
The second communication processing unit receives from the receiving device an acknowledgment packet for the packet that cannot be generated and modified at a relay point between the receiving device and the transmitting device. ,
The first communication processing unit transmits the acknowledgment packet to the transmitting device,
The communication control device is
a control unit that controls the packet or the acknowledgment packet so that the transmission device changes the transmission speed;
a target transmission speed estimating unit that estimates a target transmission speed between the transmitting device and the receiving device;
a current transmission speed estimator for estimating a current transmission speed between the transmitting device and the receiving device;
further comprising
The control unit performs the control according to the difference between the current transmission speed and the target transmission speed,
the control includes discarding a portion of the acknowledgment packet;
Communications controller. 2. The communication control apparatus according to claim 1, wherein said control includes adjustment of transmission timing of said acknowledgment packet or said packet. 3. The communication control apparatus according to claim 2, wherein said adjustment of said transmission timing includes shortening or lengthening a transmission interval between said acknowledgment packets or a transmission interval between said packets. 4. The communication control device according to claim 2 or 3, wherein said adjustment of said transmission timing comprises delaying transmission of said acknowledgment packet or said packet. The communication control apparatus according to any one of claims 1 to 4 , wherein said control includes adjustment of transmission order of said packets. the packet is a packet at least partially encrypted or authenticated;
the acknowledgment packet is an acknowledgment packet that is at least partially encrypted or authenticated;
A communication control device according to any one of claims 1 to 5 . receiving from the transmitting device a packet that is transmitted from the transmitting device to the receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device;
transmitting the packet to the receiving device;
receiving from the receiving device an acknowledgment packet for the packet, which acknowledgment packet cannot be generated and modified at an intermediary point between the receiving device and the transmitting device;
transmitting the acknowledgment packet to the transmitting device;
controlling the packet or the acknowledgment packet so that the transmitting device changes transmission rate;
a method comprising
The method includes:
estimating a target transmission rate between the transmitting device and the receiving device;
estimating a current transmission rate between the transmitting device and the receiving device;
performing the control according to the difference between the current transmission rate and the target transmission rate;
further comprising
the control includes discarding a portion of the acknowledgment packet;
Method. receiving from the transmitting device a packet that is transmitted from the transmitting device to the receiving device and that cannot be generated and modified at a relay point between the transmitting device and the receiving device;
transmitting the packet to the receiving device;
receiving from the receiving device an acknowledgment packet for the packet, which acknowledgment packet cannot be generated and modified at an intermediary point between the receiving device and the transmitting device;
transmitting the acknowledgment packet to the transmitting device;
controlling the packet or the acknowledgment packet so that the transmitting device changes transmission rate;
A program that causes a processor to execute
The program further causes the processor to:
estimating a target transmission rate between the transmitting device and the receiving device;
estimating a current transmission rate between the transmitting device and the receiving device;
performing the control according to the difference between the current transmission rate and the target transmission rate;
is designed to run
the control includes discarding a portion of the acknowledgment packet;
program.

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